ИСТИНА

Micromechanical devices with oscillating and vibrating elements find applications in different areas, including resonating filters, sensors and actuators [1], electronic cooling [2], vacuum pumping systems [3], pneumatic lines and control systems [4]. Author’s previous works [5,6] demonstrated the possibility of using oscillating elements embedded in microchannels (Fig.1) to induce separation of binary gas mixtures with disparate masses of components. Present study aims to extend previous results in several ways. First of all, papers [5,6] studied only free-molecular gas flow regime which is not very useful from practical point of view, since corresponding flow rates are very low. Present work investigates the problem in the range of Knudsen numbers from 0.1 to 10. Results demonstrate that while separation weakens with decreasing Knudsen number (Fig.2), the effect is still pronounced in transitional regime (Kn~1) and, hence, high rarefaction rates are not necessarily required for mixture separation. Secondly, previous papers discovered separation effect only in ultrasonic range of frequencies of elements oscillation (around 1 MHz and higher), while this study demonstrated that high separation factor can be also obtained in the range of low and very low frequencies (around 10 kHz and lower). It was also explained that separation effect in these two regimes is dictated by different mechanics. High separation factor in ultrasonic regime is explained by “resonance” between sound speed in gas mixture and the “wave speed” of the row of oscillating barriers. Meanwhile, high separation factor at low frequencies is induced mainly by the operation of last 1-2 barriers, which resembles periodically interrupted outflow into vacuum.